Bis thiophosphoro carbamyl lubricating oil antioxidants



United States Patent 3,537,998 BIS THIOPHOSPHORO CARBAMYL LUBRICATING OIL ANTIOXIDANTS Warren Lowe, El Cerrito, Califl, assignor to Chevron Research Company, San Francisco, Calif., a corporation of Delaware No Drawing. Filed June 17, 1968, Ser. No. 737,389 Int. Cl. C10m 1/48, N34

US. Cl. 25246.7 5 Claims ABSTRACT OF THE DISCLOSURE Bis phosphorodithio carbonyl derivatives of arylene diamines are prepared for use as ashless antioxidants and antiwear additives in lubricating oil compositions.

BACKGROUND OF THE INVENTION Field of the invention 7 Description of the prior art A number of patents have been issued in which phosphorodithioic acid derivatives are disclosed; specifically, U.S. Pats. Nos. 2,743,235, 3,317,426 and 2,494,126.

SUMMARY OF THE INVENTION Oil soluble bis phosphorodithioyl carbonyl derivatives of arylene diamines are provided, obtained by the reaction of bis diisocyanates and phosphorodithioic acid derivatives. The derivatives find use as extreme pressure agents, antiwear agents, and antioxidants in lubricating oils.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The compounds of this invention will, for the most part, have the following formula:

wherein Ar is arylene of from 6 to 12 carbon atoms and R is a hydrocarbyl group, substantially free of aliphatic unsaturation, having from 12 to 30 carbon atoms, more usually from 14 to 28 carbon atoms.

The arylene group is of from 6 to 12 carbon atoms and may have from 1 to 2 fused or non-fused aromatic rings. The aromatic ring may be substituted with from 1 to 2 hydrocarbon substituents, usually alkyl substituents, of from 1 to 4 carbon atoms. The arylene group may be a single group or a mixture of groups, for example, derived from a reactant having a mixture of arylene groups.

Illustrative patents of the arylene group are benzene, toluene, xylene, cumene, naphthalene, biphenyl, etc.

The preferred parents of the arylene group are the benzene and alkyl-substituted benzene of from 6 to carbon atoms. Usually, the amino groups on the arylene will be separated by at least 3 carbon atoms; in benzene, this will be the meta or para positions.

The hydrocarbyl group represented by R will usually be alkyl or alkaryl, preferably alkaryl. Usually, there will not be more than one site of aliphatic unsaturation, e.g., ethylenic.

Illustrative hydrocarbyl groups are hexadecyl, octadecyl, tetrapropenylphenyl, triisobutenylphenyl, dodecylphenyl, tetradecylphenyl, octadecylphenyl, eicosyl, etc.

The preferred group is the alkylaryl, wherein the aryl group is phenyl and the alkyl group is either straight chain or branched chain and is of from '8 to 20 carbon atoms.

The compositions which find use in this invention are readily prepared by combining the desired phosphorodithioic acid with the desired diisocyanate at elevated temperatures. While inert solvents may be used, they are not necessary and the reaction may be carried out neat in stoichiometric proportions. Usually, the temperature will range from about 50 to about 150 C., the time ranging from about 0.5 hr. to 12 hrs. The product may be purified and isolated by any conventional means.

The oils used for the compositions of this invention may be derived from natural or synthetic sources. Fluids of lubricating viscosity generally have viscosities of from about 35 to 50,000 Saybolt Universal Seconds (SUS) at 100 F. (V Among natural hydrocarbonaceous oils are paraffin base, naphthenic base, asphaltic base and mixed base oils.

Illustrative of synthetic oils are hydrocarbon oils, such as polymers of various olefins, generally oi from 2 to 6 carbon atoms, and alkylated aromatic hydrocarbons, and non-hydrocarbon oils, such as polyalkylene oxides, aromatic ethers and silicones. The preferred media are the hydrocarbonaceous media, both natural and synthetic.

Usually included in the oils besides the subject additives are such additives as rust inhibitors, additional antioxidants, oiliness agents, detergents, foam inhibitors,

viscosity index improvers, pour point depressants, etc.

Usually these other additives will be present in the range of from about 0.1 to 20 weight percent, more usually of from about 0.5 to 15 weight percent of the total composition. Generally, each of the additives will be pres ent in the range of from about 0.01 to 5 weight percent of the total composition.

The compounds of this invention are compatible with a wide range of other additives and, therefore, may be easily compounded with the other additives normally used in lubricating oils.

The compounds of this invention will generally be present in lubricating oils in the range of about 0.1 to 5 weight percent of the oil composition. However, the compositions may be prepared as oil concentrates and the compounds of this invention may be present in amounts as high as 50 weight percent or even higher of the total composition.

The following example is offered by way of illustration and not by way of limitation.

EXAMPLE I Into a reaction flask was introduced 17.4 g. of a mixture of 2,4- and 2,6-toluene diisocyanate (:20) and 200 g. of 0,0-di(dodecylphenyl) phosphorodithioic acid and the mixture heated and stirred at 200 F. for 6 hours. The product was then isolated and its infrared spectrum taken. Analysis: Percent P=2.7.

In order to demonstrate the eifectiveness of the compounds of this invention as extreme pressure agents, the exemplary compound of Example I was compounded in an oil composition and tested under the Falex EP Wear and Shear Test. The figures reported are the loads under which the particular lubricating oil composition failed; that is, seizure occurred. Also reported is the wear on the rod when applying a load of 850 lbs. for a period of 30 minutes. The value reported is the loss Weight in milligrams resulting from wear on the rod.

TABLE I Wear test; Shear test Rod wt. load to loss, mg. failure, lbs.

Oil without additive 17. 7 825 Oil with additive 4. 3 l, 900

An oxidation test was carried out to determine the effectiveness of the compounds of this invention as oxidation inhibitors. Oil samples were prepared with and without the additive, the same oil being used as described for the Falex Test. To 25 g. aliquots of the base oil, with and without the subject additive, were added 0.2 cc. of a solution having 3,000, 3,160 p.p.m. of copper, 2,670 p.p.m. of iron, 160 p.p.m. of manganese, 36,700 p.p.m. of lead and 1,631 p.p.m. of tin as their naphthenates, providing a distribution of metals which would be expected to be found in used crankcase oils after an L-4 Chevrolet Engine Test.

The oil sample to be tested is then maintained at 340 F. and the time required to absorb 250 ml. of oxygen observed. Without the additive, the oxygen was absorbed in 0.7 hour while the sample with the additive required 9.9 hours.

The additives of this invention may be used with lubricating oils employed in diesel engines providing effective antiwear and antioxidant activity.

The results demonstrate the excellent protection from wear and the greatly enhanced lubrication resulting by the addition of the compounds of this invention to a compounded oil. Significant oxidation inhibition is also observed. It is evident that the compounds of this invention afford excellent protection under extreme lubricating con ditions. Moreover, the compounds of this invention are compatible with a wide variety of additives which are normally included in compounded oils, as demonstrated by its activity with a common commercial ashless deter- 4 gent, e.g., alkenyl succinimides, and the corrosion inhibitor, terephthalic acid.

I claim:

1. A lubricating oil composition containing lubricating amounts of a lubricating oil and from 0.1 to 5 weight percent of a compound of the formula:

(manna, wherein Ar is arylene of from 6 to 12 carbon atoms and R is a hydrocarbyl group, substantially free of aliphatic unsaturation having from 12 to 30 carbon atoms.

2. A lubricating oil composition according to claim 1 wherein R is alkaryl of from 14 to 28 carbon atoms.

3. A lubricating oil composition according to claim 1 wherein Ar is benzene or alkyl substituted benzene of from 6 to 10 carbon atoms and the amino groups are separated by at least 3 annular carbon atoms.

4. A lubricating oil composition according to claim 1 wherein R is alkaryl of from 14 to 28 carbon atoms and Ar is tolylene.

5. A lubricating oil composition containing lubricating amounts of a lubricating oil and from 0.1 to weight percent of a compound of the formula:

wherein Ar is arylene of from 6 to 12 carbon atoms and R is a hydrocarbyl group free of aliphatic unsaturation having from 12 to 30 carbon atoms.

References Cited UNITED STATES PATENTS 2,709,156 5/1955 Bishop et al. -252-46.7 2,743,235 4/ 1956 McDermott 252-467 3,317,426 5/1967 Lowe 252-467 3,446,738 5/1969 Chao 252-46] DANIEL E. WYMAN, Primary Examiner W. H. CANNON, Assistant Examiner U.S. C1. X.R. 

